so my gf was telling me that she wanted to try having group sex but we never found anyone to do it with us. and some acquaintances that we had (open minded friends) was like, "what?" like we were crazy. so came up to a thinking if group sex is common. i know it's not socially accepted but definitely not discreet as well.

I would certainly be interested to know how common it is!
It's something I've been interested in a lot! I've been to an adult party once where people had sex in one room but I was with my ex at the time and didn't want to partake so we went off and played with ourselves.
Now that I'm single - I would certainly like to know where they happen and how often! (well in Englans anyway )

We've had group sex on a few occasions (just this past weekend, too!). For us it's been about chemistry and couples that are as open as we are. It's a lot of fun! Common? Uh, I guess I dunno, but it does happen in the real world.

It depends on what you are referring as group sex. If a threesome is group sex, it's extremely common. Almost everybody I know has had a 3some. Two couples is not quite as common from what I've noticed, especially when swapping is involved, but it does take place pretty often. As far as what I concider group sex, like swingers clubs, or orgies, that is not as common. Most people can't deal with seeing their spouse getting fucked. But this is just my insight. It may differ depending on your friends or the type of people you know.

It has been my experience that it happens more by fluke than actually being an organized event. I have been to a few parties/events where after the booze starts flowing, people start doing what they do.